1. Technical Field
The present invention relates to a signal modulation technology applied to a communication system, and in particular, to a modulation method for improving signal conversion gain and a high-gain modulator thereof.
2. Related Art
With the need for high speed and mobility communication, various wireless communications have been developed. In addition to conventional call function, a wireless communication apparatus also needs to support services such as high-definition video function, application software, and Wi-Fi. A modulation circuit is one of the important circuits in a wireless communication apparatus.
FIG. 1 is a general block diagram of a radio frequency (RF) transmitter. Referring to FIG. 1, a radio frequency transmitter circuit 100 mainly consists of a digital-to-analog conversion circuit 110, a modulation circuit 120, a driver circuit 130, a power amplifier 140, a band-pass filtering circuit 150, and an antenna 160.
First, a baseband signal S1 is converted into a baseband analog signal by the digital-to-analog conversion circuit 110, and is sent, in the form of an in-phase signal I and a quadrature signal Q, to the modulation circuit 120 for processing. Subsequently, the modulation circuit 120 modulates the in-phase signal I and the quadrature signal Q to output a modulated signal S2, and then the modulated signal S2 passes through the driver circuit 130 and is amplified by the power amplifier 140. Finally, the band-pass filtering circuit 150 passes the modulated signal, the modulated signal is sent to the antenna 160 so that the modulated signal is transmitted.
In a high-speed data transmission environment, with the increase of the signal transmission rate, the power consumption of the modulation circuit also increases.